Valve seat insert



Aug. l, 1950 H. c. KARCHER E-rAL. Y2,517,114

` VALVE 4slim INSERT Filed Aug. 28, 1947 Patented Aug. 1, 1950 QFFIICEHarry C. Karcher and Dimitrius Grerdan;v ndianapolis, Ind., assignorstofGeneral Motors'Cor-` poration,"Detroit, Mich., a corporation of Dela-'Wavre npnli'canmaugst 2,8, 1947, `serial No. nugget j f.; volaims. (c1.12s-18s) y The present invention generally relates to valve 1 mechanismsand more particularly to valve seat inserts.`

The principal object of the invention is to provide a valve inserthaving spaced surfaces "for tight engagement with the surface of a hightemperature gas passage in a valve body of an engine and a relievedintermediate surface provided with a low melting point coating toprovide clearance between the coating and the passage surface andthereby prevent distortion of the insert upon expansion and contractionof the body due to differences in engine operating temperature, the hightemperature gas passing through the passage and the valve seat insertcausing melting of the coating of the insert to insure efcient transferof heat between the insert and the valve body.

The means by which this object is accomplished will become apparent byreference to the following detailed description of and drawingillustrating these means.

Figure 1 is a sectional view of a portion of a valve body and a, valveseat insert in a passage of the body and a poppet valve seated thereon.

Figure 2 is a View similar to Figure 1 illustrating the method by whichthe valve seat insert is secured in the valve body passage.

Figure 3 is a perspective View of the valve seat insert shown in Figuresl and 2 with parts broken away and in section to show the novel detailsthereof.

As shown in the drawings the valve seat insert, generally indicated atI, is of annular form and is provided with a longitudinal bore 3 withoutwardly tapered end portions 5 1, a shank portion 9 adjacent one end,of small outside diameter, and a flange portion I I adjacent the otherend of larger outside diameter. The outer end face of the flange portionII is provided with a tapered annular valve seat portion I3, on which apoppet valve i5 is shown seated in Figure 1. A V-shaped peripheralprojection or flange I1 is provided on the flange portion II adjacentthe outer end face and a tapered annular peripheral surface 2| isprovided on the inner end face of the flange portion II. As seen inFigures 2 and 3 the tapered surface 2l and the outer cylindrical surface23 of the ange portion II adjacent the V-shaped projection or iiange I1is coated with a low melting point metallic coating 25 which is adaptedto melt at normal operating temperature of the valve insert. The outerend of the shank portion is provided with an external tapered surface 21and an external `groove 29 is provided thereon adjacent-the inner endface of the fiange portion II.

' The above describled'valve insert I is tightly secured inva passage 3l"in an engine cylinder head or blocker a valve body 33 havingcounterbores 345-31, adjacent one Yend of the passage 3| of dimensionssuch-` that upon heating andexpansion of thevalve body and/or coolingand contraction of thevalve insert from a, giventemperaturethe"V-shapedprojection or flange II may be pressed into thelarger counterbore 35 of the passage 3| and the shank portion 9 may bepressed into the smaller counterbore and the face of the anged portionII of the valve seat insert is tightly seated on the face of the valvebody between the counterbores. Upon the: return of the valve body andinsert to this given temperature the V-shaped projection or flange I1and shank 9 of the insert will be in tight engagement with the internalsurfaces of the body counterbores 35-31 and clearance will be leftbetween the coated surface of the insert and the counterbore 35.

For normal operating temperatures of the valve insert and body the lowmelting point coating 25 of the insert will melt and partially fill theclearance space between the insert and body and the V-shaped projectionIl and shank portion 9 will remain in tight engagement with the internalsurfaces of the counterbores 35-31 of the valve body 33 to preventescape of this molten coating which serves as an efcient heattransferring medium in the clearance space between the insert and body,which space prevents distortion of the valve seat insert by relativeexpansion and contraction of the valve body.

The above described Valve construction is particularly adapted tointernal combustion engines to prevent overheating and distortion of theexhaust valve seats and to prolong the life thereof.

We claim:

1. A valve seat insert for an internal combustion engine having spacedend portions and a relieved portion therebetween coated with a materialwhich melts at normal engine operating temperatures of the valve seatinsert to provide a fluid heat transferring nlm.

2. An annular valve seat insert for an internal combustion engine havingspaced external end portions and a relieved exterior surfacetherebetween having a coating adapted to melt at normal engine operatingtemperatures of the valve seat insert to provide a fluid heattransferring medium.

3. An annular valve seat insert for an internal combustion engine havinga seat on one end, a narrow external end portion adjacent said seat, anindirect external portion having a coating which melts at normalengineoperating temperature of the valve seat insert between the externalflange and the `A.oppositeend portionofsaid valve insert.

4. An annular valve seat insert for an internal combustion engine havinglarge and small outside diameter portions at opposite ends, said largediameter end portion `having a narrow :external ange portion adjacentthe outer iendiaceandfa 3 coating thereon adapted to'im'el't at vnormal,engine operating .temperaturen :the val-ve insert.

' 5. An annular valve seat insert for an internal :combustion enginehaving large andsmall outside diameter portions adjacentthe 'oppositeend faces, said large diameter portion having. fafs'eating surface onthe outer end face and a narrow i `il -shaped external flange .adjacentthe fouterend face and a, coatingllon "the .remaining portion .ofthefexterior ofzsaid. largediameter portion adapted `tomeltatnormal'.engin'e1-operating tempera- .turenf .thevalverinsertfandtserverasra'ffluid heat transferring medium.

, .6. A valve mechanism for lan internal combustion engine includingavalveibodylhaving arpassage therein anda valvefseatiinsert havingspacedportionsiadjacent .theends Afiorengagement `with 4 the wall of thepassage in the valve body and an intermediate portion spaced from thepassage wall coated with a material adapted to melt and provide aiiuidheat conducting lm between the insert and the wall of the valve bodypassage and allow relative .expansion Aand v`contraction therebetween.

'7. A valve mechanism for an internal combus- :tion engine including avalve body having a, passage provided with counterbored portions, avalve *seat insert having spaced external portions in tight .engagementwith the walls of the counterbored portions ofthe passage in the body,an angnularxsurace vseated on the surface of the body between thecounterbored portions, and a coated .external surfacespaced from one ofthe internal surfac'es ci' "the valve seat insert between the seatingandone pair of engaging surfaces, the coating of said spaced surface beingadapted to melt for normal :engine operating .temperatures ofthe bodyrand valve seat insert .for :providing an efcient fluid heattransferring lrn between the .bodyand the valve seat winsertand forallowing relative expansion and contraction ,therebetween.

, HARRY C KARCHER.

DIMITRIUS. GERDAN.

No references cited.

